Mini-Split and Ductless HVAC Permit Requirements in California: 2026 Contractor Guide

Ductless mini-splits and multi-head heat pump systems are one of the fastest-growing segments of the California HVAC market. They are perfect for ADUs, room additions, retrofits where running new ducts is impractical, and homeowners who want zoned comfort without a full ducted system.

The mistake many contractors make is assuming that “ductless” means “simpler permitting.” It does not. These systems still require mechanical permits, almost always require electrical permits, and the 2025 Title 24 rules (now fully enforced in 2026) have specific requirements for verification methods, fan efficacy, and load calculations that are different from a traditional split system.

This guide walks through exactly what is required, what changed in the current code cycle, and the documentation mistakes that turn a fast mini-split install into a three-week correction loop.

Yes — You Still Need a Mechanical Permit (and Usually Electrical)

There is no like-for-like exemption for mini-splits. Every new installation or replacement of a ductless or multi-head system requires a mechanical permit in California. The mechanical permit covers the outdoor unit(s), indoor heads, refrigerant lines, condensate drainage, and any short duct runs on ducted mini-split models.

Most installations also require an electrical permit for the dedicated circuit(s), disconnect(s), and any panel or subpanel work. Some jurisdictions (San Jose and parts of Santa Clara County) will bundle this as a combined “HVAC changeout” permit. San Francisco DBI almost always keeps the mechanical and electrical permits separate and routes them through different intakes. Oakland sits in the middle.

The same rules we cover in heat pump permit requirements apply here: if you are adding significant new load, expect the building department to ask for a load calculation under NEC Article 220.

Title 24 Rules Specific to Mini-Splits and Multi-Head Systems

Equipment efficiency minimums are the same as other heat pumps: SEER2 15.0 and HSPF2 7.8 for systems under 65,000 BTU in most climate zones. The compliance path is favorable for heat pumps, which is why so many ADU and retrofit projects are choosing them.

The differences show up in verification:

• Many ductless and multi-head systems cannot use the standard HERS refrigerant charge verification procedures that assume longer line sets and accessible coils. These systems must use the weigh-in charging method per the Reference Residential Appendices (RA3.2).
• Fan efficacy and airflow requirements still apply to any forced-air components. The CEC removed some proposed exceptions in the final 2025 code that would have allowed simply summing airflows across multiple heads. Each zone that has measurable airflow needs to meet the applicable criteria.
• Load calculations (Manual J) are increasingly requested by plan reviewers on ADU and addition projects. Oversizing a multi-head system kills both efficiency and comfort, and some inspectors are now requiring the documentation to back up the equipment selection.

The full context on climate zones, CF-1R generation, and the 2025/2026 efficiency minimums is in our Title 24 HVAC requirements in 2026 guide.

HERS Verification for Ductless Systems

HERS testing is required on the vast majority of mini-split installs in California. What changes is the method:

• Refrigerant charge: Weigh-in method for most ductless and multi-head systems. The installing contractor must document the exact refrigerant weight added and the HERS rater confirms the documentation and system performance.
• Airflow verification: Required for any heads or short duct runs that deliver forced air. The 350 CFM per ton minimum still applies where the system can be tested that way.
• Duct leakage: Only required if you are replacing or altering more than 40 feet of existing duct or substantially changing the duct system. A pure ductless multi-head install with no new ducts usually skips this test.

Schedule the HERS rater at the same time you book the install. In busy Bay Area months the good raters are booked a week or more out, and you do not want the final inspection waiting on a test that has not happened yet.

Panel and Electrical Considerations

Each outdoor unit (or grouped set of heads on a multi-zone system) typically requires its own dedicated circuit with a local disconnect. On a 3-ton multi-head system you can easily be adding 30–50 amps of new load that did not exist before.

If the existing panel is already near capacity, the building department will require the load calculation. In many cases the homeowner does not want to wait 4–8 months for a PG&E service upgrade, so the practical solution is a listed load management device that sheds non-critical loads when the mini-split is running at high demand. That device has to be specified on the permit and the inspector has to recognize the model.

The same electrical permitting rules and common mistakes we cover in electrical permit requirements in California apply directly to mini-split work.

Bay Area Fees and Timelines

Mini-split permits generally fall into the same fee ranges as heat pump changeouts: roughly $250–$700 depending on the jurisdiction once you include the electrical sub-permit and issuance fees. HERS verification is a separate third-party cost of $150–$300.

OTC eligibility is higher for simple 1:1 replacements in most peninsula cities. Anything involving an ADU, room addition, panel work, or submitted in San Francisco or Oakland will go through plan review and typically takes 1–3 weeks for a clean submission. We have the full city-by-city numbers in HVAC permit costs in the Bay Area and how long an HVAC permit takes in California.

The Most Common Mini-Split Permit Mistakes

The failures we see repeatedly on ductless jobs:

• Assuming “no ducts = no Title 24 or HERS” and submitting a CF-1R that is missing the required verification methods.
• Using the standard superheat/subcooling refrigerant charge procedure on a system that requires weigh-in documentation.
• Not listing every indoor head model number accurately on the permit (supplier substitutions at the last minute create mismatches the inspector catches).
• Filing the electrical permit days or weeks after the mechanical permit in cities that expect coordinated review.
• Skipping the Manual J when the project is an ADU or addition and the plan reviewer asks for it.
• Designing a multi-head system that serves three zones but only documenting load for the largest zone.

These are preventable with the same discipline we recommend in how to pull an HVAC permit in California and 7 permit filing mistakes that cost contractors weeks.

Rebates and Why the Permit File Still Matters

TECH Clean California, BayREN, and federal IRA incentives treat mini-split heat pumps the same as central systems. A closed permit with passed final inspection is required before they release funds. Many ADU projects are using mini-splits precisely because they qualify for these incentives — see our new guide on ADU permit requirements for the bigger coordination picture.